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  • How to Use the Nordic NRF905 Transceiver With a Raspberry Pi

    Hi! Thank you very much for these insights and no worries at all.I have checked the crystal and it is the 16.000 model, so we are good there. As for the addresses, I now have much better a understanding than when I started using the module. I cannot help but wonder why Nordic did not consider it important enough to reference in their technical documentation. Maybe I have also overlooked it, who knows. Also, thanks for pointing out the aerial configuration which is different for any given frequency range. Since I am mostly interested in 433 MHz, the built-in aerial was a perfect fit. :-)Part of the confusion I had over not receiving anything at all is due to the fact that I was initially experimenting with very simple hardware such as those RF-enabled wall sockets you can buy everywhere....

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    Hi! Thank you very much for these insights and no worries at all.I have checked the crystal and it is the 16.000 model, so we are good there. As for the addresses, I now have much better a understanding than when I started using the module. I cannot help but wonder why Nordic did not consider it important enough to reference in their technical documentation. Maybe I have also overlooked it, who knows. Also, thanks for pointing out the aerial configuration which is different for any given frequency range. Since I am mostly interested in 433 MHz, the built-in aerial was a perfect fit. :-)Part of the confusion I had over not receiving anything at all is due to the fact that I was initially experimenting with very simple hardware such as those RF-enabled wall sockets you can buy everywhere. The thing is however, they are so simple that they do not make use of any addresses or checksums and the signal itself is OOK coded. No wonder nRF905 could not pick up any of it with its GFSK modulation.Would it be possible to operate the circuit in some sort of promiscuous or raw mode where you could directly see any of the preambles or what you call distinguishable structure, e.g. the 0101010101 sequence?With regard to the inline resistor, I had actually thought as much before I even considered asking this question. The thing is though, a single RPi GPIO port or pin can take a current as high as 16 mA or if you were to use them all at once this value would even go down to 2 mA per port. Those are at least the parameters I once stumbled upon. Now, since you have opted for a 220 Ohm resistor the resulting current in the example you have mentioned would be 15 mA, which is pretty darn close to the maximum value. ;-)Many thanks again for your time, much appreciated!

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  • How to use the Nordic nRF905 Transceiver with a Raspberry Pi

    Hi. I have followed your instructions up to the point of successfully compiling and loading the kernel driver, but I cannot receive anything at all with my nRF905-based PTR8000+ module. The configuration I am using is the one you have provided above. Can you please explain what the TX and RX addresses are for and what "ABCD" really means in that context? Is there anything I can do to get error-related / debug information out of the driver?Can you please also explain what the 220 Ohm inline resistor is for at the DR pin connection? According to specs, the DR current is limited to 0.5 mA, so that ideally no limiting resistor is required at all.Many thanks for your excellent work!

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